1. Field of the Invention
The invention generally relates to manholes and barrier systems for manholes. More particularly, the invention relates to a barrier security system configured to be used with any existing or new manhole to prevent the dumping of unwanted or hazardous materials into the manholes or other unauthorized access to manholes while enabling the release of water or other liquids therefrom.
2. Discussion of the Related Art
Manholes are commonly utilized as underground utility access points for performing repair, upgrading, and maintenance on underground or otherwise buried public utility services such as sewers, telephone, electricity, cable, fiber optics, storm drains, gas lines, steam lines and other similar facilities. Manholes are typically found in urban areas and are usually located within public and private easements, public right of way, and other access rights that allow work on the facilities. Manholes exist within public access areas including existing streets and sidewalks or other surface structures. Manholes generally comprise an access hole at street and/or ground level and an access shaft or riser extending upwardly from the manhole diameter transition section, normally referred as the cone, to the ring and cover. They may include ladders, stairs or other mechanisms that permit utility workers to descend down the access shaft, however where confined space entry requirements govern the access, the workers are lowered by a cable into the manhole and have protective clothing and breathing apparatus. A manhole cover, usually a metal disc or other shape and material, is typically placed over the manhole to prevent accidental or otherwise unauthorized access to the manhole.
Unauthorized access to a manhole can result in theft and illegal dumping of debris and grease into the sewer. Commercial grease haulers typically have trucks capable of carrying 3,000 to 4,000 gallons of grease collected from grease traps and grease interceptors from restaurants and other food service facilities. To cut costs and maximize profits, disreputable commercial grease haulers remove the existing manhole cover and dump the collected grease down the manhole rather than disposing of the grease properly at an authorized disposal site. As the grease flows down the manhole and through the associated pipes, it cools and congeals, collecting on roots and other debris or obstructions in the sewer. As such, the grease forms a blockage, inhibiting or even preventing the natural flow of sewage therethrough and results in backup and sewer overflow. In addition, other hazardous materials are capable of being disposed of through manholes, thereby creating a variety of environmental hazards.
Manhole security systems are desired for other reasons as well. For instance, sewers and the like, regrettably, pose an attractive point of access and hiding place for criminals or even terrorists and their wares. Still other unauthorized access to manholes include the removal or theft of wiring, cable, pipes, and other materials of value
A variety of manhole security systems have been developed for preventing unauthorized access to existing manholes. Such security systems typically utilize an insert configured to be coupled to a lip of the manhole ring by being hooked under or otherwise latched thereto. The insert serves to provide a barrier to prevent the dumping of liquids into the manhole. However, a large number of existing manholes do not have a lip on the ring of the manhole. Accordingly, existing security systems are incapable of being used with manhole rings of this type. Existing security systems also must be removed for street improvements and thus do not remain in place to catch construction debris.
In addition, prior systems generally require relatively expensive and time-consuming drilling and/or bolting operations in order to install the inserts in the manhole. Other prior systems have utilized intricate and costly mechanisms that corrode over time.
Prior designs at least essentially completely sealed the manhole, thereby preventing release of sewage that would otherwise exit from the sewer by the hydraulic lifting of the manhole cover in a back-up situation. Without the capability of exiting through the manhole, sewage is capable of backing up into homes and businesses, resulting in expensive clean-up, restoration, and replacement of damaged property.
Prior designs utilize the existing ring and cover for locking. The ring and cover are removed during street repaving and construction to allow for the ring to be raised to the new street level, resulting in an unprotected opening in the manhole allowing construction debris enter the system and cause a sewer blockage
The need therefore exists to provide a manhole security system that is relatively simple to maintain and is robust enough to withstand the rigors associated with operation of such systems.
The need also exists for manhole security system that can be quickly and efficiently assembled and maintained.
Further, the need also exists for a manhole security system that may be installed on a variety of existing manhole structures such as those having a lip as well as those without a lip.
Further, the need exist for a manhole security system that can be installed below the existing ring and cover prior to construction and remain installed in the manhole after completion of construction to protect against future dumping. Such a design would provide continuous protection from blockages and eliminate the potential for the need for expensive confined space entry to remove construction debris.